I got some shotgun powder to try (name is unknown, nor there are loading data online, only what I had for shot shells).
I put 10gn of it, and got a 225 m/s on my Chrony.
With 12 grain, it read 410 m/s.
I haven't observed any deformation on the brass, but one out of 7 primers went a bit out (not the 12 gn one), and cases I used are some military brass with berdan primers in them.
Tomorrow, I shall load with 10,1 10,2 10,3 gn etc and use proper Winchester primers to try.
For the bulkiness, with 17 gn of it its a case full, with 10 its about 60% case full.
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Yugo M48 8x57 Military
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